Torque Converter Clutch Solenoid

This procedure replaces the torque converter clutch (TCC) solenoid in the 6L80 automatic transmission by removing the transmission pan and valve body to access the internal solenoid assembly.

Warnings

Tools required

Parts

• Torque converter clutch solenoid assembly × 1 — AC Delco 24230371 or equivalent
• Transmission pan gasket × 1 — Use OEM specification
• Transmission filter assembly × 1 — AC Delco 24278367 or equivalent
• Transmission pan bolts (if corroded) × 20 — M8 x 1.25 x 25mm
• Valve body cover gasket/seal × 1 — Use OEM specification

Fluids

• ACDelco Dexron VI ATF — 11.5 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Chock rear wheels securely
3. Disconnect negative battery cable to prevent accidental starter engagement
4. Raise front of vehicle and support securely on jack stands at frame rails
5. Allow transmission to cool completely if vehicle was recently operated
6. Remove engine splash shield/skid plate if equipped (retain hardware)
7. Position large drain pan under transmission pan area
8. Have all replacement parts and fluids ready before beginning disassembly

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission pan at the bottom of the transmission. Loosen all pan bolts approximately 2-3 turns but do not remove. Starting at one corner, carefully loosen and remove bolts from that corner first to allow pan to tilt and drain fluid in a controlled manner. Keep hands clear as fluid begins to flow. Once majority of fluid has drained, remove remaining pan bolts.
2. 2

   Remove transmission pan and filter
   Carefully lower the transmission pan, being mindful that residual fluid will still be present. Set pan aside for cleaning. Locate the transmission filter held by 2-3 bolts at the valve body. Remove filter mounting bolts and carefully pull filter straight down to remove. Note the position of any O-rings or seals on the filter neck.
3. 3

   Clean pan and inspect magnet
   Thoroughly clean the transmission pan using brake cleaner and shop rags. Remove the magnetic drain plug and inspect for metal shavings. Small amounts of fine metallic dust are normal, but excessive chunks or debris indicate internal wear. Clean the pan gasket mating surface with plastic scraper, ensuring no old gasket material remains. Clean magnet thoroughly before reinstalling in pan.
4. 4

   Identify and access TCC solenoid location
   Look up into the transmission case at the valve body assembly. The TCC solenoid is part of the control solenoid assembly mounted to the valve body. It is typically located on the driver's side of the valve body. Before removing valve body components, photograph or mark the wiring harness routing and connector positions for reassembly reference.
5. 5

   Disconnect internal wiring harness
   Locate the internal transmission wiring harness connectors that connect to the control solenoid assembly. These are typically square or rectangular multi-pin connectors. Carefully depress the locking tabs and disconnect each connector. Note the color coding and position of each connector. Use marker to label if needed.
6. 6

   Remove control solenoid assembly cover
   The control solenoid assembly is covered by a metal or composite cover plate secured with multiple small bolts. Remove these cover bolts in a criss-cross pattern to prevent warping. Keep bolts organized as they may be different lengths. Carefully remove cover and note the position of any check balls or springs that may be present underneath.
   Torque spec

   Cover Screws14 Nm (10 lb-ft)
7. 7

   Remove TCC solenoid from valve body
   The TCC solenoid is secured to the valve body with small bolts or is part of the solenoid assembly. Remove the sensor/solenoid mounting bolts holding the TCC solenoid in place. Carefully pull the solenoid straight out to avoid damaging the valve body bore. Note the orientation and position of any O-rings, seals, or alignment pins on the solenoid body.
   ⚠Do not allow any debris or foreign material to enter the open valve body passages. Cover openings with clean shop towels if needed.
   Torque spec

   Sensor Bolts14 Nm (10 lb-ft)
8. 8

   Install new TCC solenoid
   Compare new TCC solenoid to old unit to verify correct replacement. Lubricate new O-rings on solenoid with clean Dexron VI ATF. Carefully align solenoid with valve body bore, ensuring proper orientation per service manual or markings. Push solenoid fully into position until seated. Install and hand-tighten mounting bolts, then torque to specification in a criss-cross pattern.
   Torque spec

   Sensor Bolts14 Nm (10 lb-ft)
9. 9

   Reinstall control solenoid cover
   Inspect cover gasket or seal and replace if damaged or included with new solenoid. Ensure any check balls or springs are in their correct positions per service manual. Carefully position cover over solenoid assembly, aligning all bolt holes. Install cover screws and hand-tighten, then torque in criss-cross pattern to prevent warping.
   Torque spec

   Cover Screws14 Nm (10 lb-ft)
10. 10

    Reconnect internal wiring harness
    Reconnect all internal transmission wiring harness connectors to their corresponding solenoid assembly locations. Ensure each connector clicks firmly into place and locking tabs engage fully. Verify wiring harness routing matches original configuration and does not interfere with any moving components or valve body passages.
11. 11

    Install new transmission filter
    Install new O-ring or seal onto filter neck, lubricating with clean ATF. Align filter with valve body mounting location and push straight up until fully seated. Install filter mounting bolts and tighten securely. Ensure filter is not crooked or misaligned, as this can cause leaks or flow restrictions.
12. 12

    Install transmission pan with new gasket
    Position new transmission pan gasket on pan or transmission case per manufacturer instructions (some gaskets adhere to pan, others to case). Carefully raise pan into position, aligning all bolt holes. Start all pan bolts by hand to ensure proper thread engagement. Tighten pan bolts in a criss-cross pattern starting from center and working outward. Torque all bolts to specification in sequence to ensure even gasket compression.
    Torque spec

    Pan Bolts20 Nm (15 lb-ft)
13. 13

    Refill transmission fluid
    Locate transmission dipstick tube at rear of engine compartment (driver's side). Using a long-neck funnel, add approximately 5 quarts of Dexron VI ATF initially. Start engine and allow to idle in Park. With engine idling and transmission in Park, check fluid level on dipstick. Add fluid in 1/2 quart increments until level reaches cold range on dipstick. Do not overfill.
14. 14

    Perform transmission relearn procedure
    With engine running, apply brake and shift through all gear positions (P-R-N-D-L) pausing 3 seconds in each position. Return to Park. This allows the transmission control module to relearn shift points and adapt to the new solenoid. Check for any transmission warning lights or codes using scan tool if available.
    ℹ️Some vehicles may require a scan tool to perform a full transmission adaptation/relearn procedure for optimal shift quality.

Reassembly

1. Reinstall engine splash shield or skid plate using original hardware
2. Lower vehicle from jack stands carefully
3. Reconnect negative battery cable
4. Remove wheel chocks

Verification

• Start engine and verify no transmission fluid leaks from pan gasket area while engine idles
• With engine at operating temperature, shift through all gears and verify smooth engagement without slipping or harsh shifts
• Check transmission fluid level with engine running, transmission in Park, on level ground. Fluid should be in hot range on dipstick
• Test drive vehicle and verify TCC lockup occurs properly (RPM drop at highway speeds when lockup engages, typically 40-45 mph)
• Scan for any transmission diagnostic trouble codes using OBD-II scanner. No TCC-related codes (P0741, P0742, P0743) should be present
• Monitor transmission temperature gauge during test drive to ensure normal operating temperature
• Recheck fluid level after test drive and top off if needed, checking again for leaks at pan gasket

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